Heat a wok or large saucepan over high heat. Swirl in 1 tablespoon vegetable oil. Spread chicken mixture in a single layer over the surface of the wok; cook for 1 minute. Flip and toss chicken. Spread out again; cook and stir for 2 minutes more. Transfer chicken to a plate.

Heat remaining 2 tablespoons vegetable oil in the wok over medium heat. Add light green part of the scallions, garlic, and ginger; cook and stir until fragrant and softened, 1 to 2 minutes.

Make a well in the center of the wok; pour in beaten eggs. Stir eggs with a spatula until scrambled, about 2 minutes. Stir in chicken, remaining 1 tablespoon soy sauce, remaining 1 teaspoon sesame oil, dark green parts of the scallions, pineapple, peanuts, and rice vinegar.